There are tabs along the top of the casing. I scuffed the ones around the fluid reservoir because I didn't take the time to remove the entire thing like I should have, but it's really easy to pop them open and add the wires to the rest that are there.
I'm really pissed now!!! I bought the regular D2 Dually set. I want the side shooters now! I'll have to find another application for the set I bought so I can have an excuse to replace them!